Eccoboom!

[yamahaSHO]

Carbon buildup has always been in issue with engines in general and has always caused the compression to go up. One of the ways people have been dealing with this on older vehicles is using higher octane fuel. IMHO, the use of lower octane fuel is a selling point to the average customer.

Higher octane fuel would definitely help in a situation such as this. It's resistance to burn would be higher would would help mitigate the issue if there were a hot spot. Additional charge cooling, water/meth injection and colder plugs are all ways people deal with this sort of issue. If the carbon is actually burning, I'd imagine it would follow with flaking off and heading out the exhaust. Generally, places that are seeing knock or pre-ignition will be free of carbon if it is happening regularly.

I run injector cleaner every now and again, but I stay away from boost until I've gone through a tank. As far as cleaning the combustion chamber/pistons/ect, I'm guessing my water injection does a fairly good job.

I agree with SHOZ123. If you're sucking the blow-by back through the intake, it's only going to dirty things up and lower octane.

 

[abs99]

The ecoboost engine has a special PCV configuration using an upside down U-Pipe, the equivalent of a catch can and, on most engines, a heated element where the PCV stream enters the intake. The PCV would still be scavenging blow by in cases where there was a significant amount, but heavy particles probably will enter the intake a relatively low rate compared to other DI engines.

With respect to higher octane, I'm not sure if the higher octane will help if an edge of the carbon on the piston crown is glowing red. Knock/detonation is different than pre-igntion. Octane will absolutely help with detonation, but remember detonation happens when the piston is already close to TDC and occurs due to a combination of pressure and temperature and not due to a secondary ignition source. Pre-ignition happens due to a secondary ignition source and often occurs far before TDC. It is this fact that makes it so likely to damage a piston - the pressure build up as the piston is compressing the gases in the chamber combined with the concurrent expansion of gases in the chamber due to the very early ignition results in a massive pressure spike - one much greater than would ever be seen with typical knock/detonation behavior. The fact that these engines are blowing up with melted or holes in pistons and seem to have carbon build up issues is why I suspect pre-igntion. Fuel of any octane will ignite when exposed to an ignition source irrespective of octane. Octane simply prevents detonation by raising the temperature and pressure thresholds.

 

[yamahaSHO]

With respect to higher octane, I'm not sure if the higher octane will help if an edge of the carbon on the piston crown is glowing red.

Octane will definitely help. Reducing timing marginally will not.

Knock/detonation is different than pre-igntion. Octane will absolutely help with detonation, but remember detonation happens when the piston is already close to TDC and occurs due to a combination of pressure and temperature and not due to a secondary ignition source. Pre-ignition happens due to a secondary ignition source and often occurs far before TDC.
It is this fact that makes it so likely to damage a piston - the pressure build up as the piston is compressing the gases in the chamber combined with the concurrent expansion of gases in the chamber due to the very early ignition results in a massive pressure spike - one much greater than would ever be seen with typical knock/detonation behavior. The fact that these engines are blowing up with melted or holes in pistons and seem to have carbon build up issues is why I suspect pre-igntion. Fuel of any octane will ignite when exposed to an ignition source irrespective of octane. Octane simply prevents detonation by raising the temperature and pressure thresholds.

I totally know the difference. Resisting combustion is resisting combustion. It doesn't care where it's at.

Detonation is after normal combustion is initiated by the spark plug. Pre-ignition occurs any time before the spark plug fires on the compression stroke, regardless of what distance it is from the chamber. Very early pre-ignition events do not give a massive pressure spike. They combust, and then the combusted hot gasses are compressed creating more heat... This is why you don't hear pre-ignition.

 

[abs99]

Octane will definitely help. Reducing timing marginally will not.



I totally know the difference. Resisting combustion is resisting combustion. It doesn't care where it's at.

Detonation is after normal combustion is initiated by the spark plug. Pre-ignition occurs any time before the spark plug fires on the compression stroke, regardless of what distance it is from the chamber. Very early pre-ignition events do not give a massive pressure spike. They combust, and then the combusted hot gasses are compressed creating more heat... This is why you don't hear pre-ignition.

Thanks for clarifying this. You are right. The pressure spike occurs with detonation and no spike with pre-ignition. Pre-ignition occurs before the spark plug fires, detonation after the plug fires. Pre-ignition causes extreme pressures and heat in the combustion chamber due to gases expanding from combustion while the piston is moving to TDC and trying to compress the gas at the same time. Detonation, although it causes the pressure spike happens after the spark has fired and as a result the forces from the pressure spike are consistent with the movement of the piston, down, so the chances of damage is lower and many engines operate within normal parameters with some mild detonation. Few engines can survive pre-ignition.

I would still bet heavily that the engine failures some folks have experienced is due to pre-ignition and not detonation.

 

[yamahaSHO]

I don't doubt that at all, however, I do believe higher octane will heavily prevent this.

 

[blaine109]

Can either pre-ignition or detonation cause the RPM's to fluctuate during acceleration or sustained speeds driving? I'm having a **** of a time getting my car to run correctly and it is jerky on acceleration with the rpm needle bouncing around. I have a thread called "What's Wrong with the SHO" going on about all my issues.

 

[zak]

The ecoboost engine has a special PCV configuration using an upside down U-Pipe, the equivalent of a catch can and, on most engines, a heated element where the PCV stream enters the intake. The PCV would still be scavenging blow by in cases where there was a significant amount, but heavy particles probably will enter the intake a relatively low rate compared to other DI engines.

.

The Ford powertrain VP also pointed us to a labyrinth PCV filter located below the intake manifold, when I questioned him about build up of residues in the intake (direct injection = no washing of the intake tract with fuel).

 

[Showgun]

The Ford powertrain VP also pointed us to a labyrinth PCV filter located below the intake manifold, when I questioned him about build up of residues in the intake (direct injection = no washing of the intake tract with fuel).

Is that filter visible with the engine cover off? I'd like to locate that and check it out and maybe do some maintenance on it.
TNX.

 

[SHOZ123]

Still needs a catch can on both sides of the PCV system. The one on the ecoboost IIRC is a chamber with steel wool in it that drains into the crankcase. One it will only stop liquid, gases will go right through like the normal PCV systems out there.

And under boost you will be pushing this stuff out into the intake track in front of the turbo somewhere through the valve cover(s).

 

[yamahaSHO]

The Ford powertrain VP also pointed us to a labyrinth PCV filter located below the intake manifold, when I questioned him about build up of residues in the intake (direct injection = no washing of the intake tract with fuel).

Fuel injectors on non-DI motors won't wash the intake. They're only a few inches from the cylinder/chamber with where they would be installed on the head. Dirty intake manifolds aren't dirty due to DI. Most likely they're dirty from crankcase blow-by.

Still needs a catch can on both sides of the PCV system. The one on the ecoboost IIRC is a chamber with steel wool in it that drains into the crankcase. One it will only stop liquid, gases will go right through like the normal PCV systems out there.

And under boost you will be pushing this stuff out into the intake track in front of the turbo somewhere through the valve cover(s).

If you can get the oil separated, running the gasses back into the intake is fine as I'd rather have vacuum on the crankcase.

I would imagine that Ford's setup isn't a desireable one for what 'gearheads' would want. Something like this would work nicely. I have a non-universal one for my Subaru.

 

[SHOZ123]

I use cheap ebay ones on my car. One on each side of the motor. Both inline with OEM plumbing.

 

[yamahaSHO]

The one I posted above will do a much better job at separating the oil. It also can be drained back in and had ports to tap off your cooling system for cars that are driven in cold weather.

 

[SHOZ123]

It has always been my contention that most of what goes through the PVC system is a gas and not liquid oil. The OEM oil separator stops most of the oil. The gases though need to be condensed to adequately get it out of the system.

 

[EcoBrick Bob]

I have "Catch Cans" on both my G8's. Talked with Torrie & others about one for EB Engine but no one is exactly sure where to install .

When I installed my W/M system I pulled the TB & checked out the condition of the intake. There was no carbon buildup, like there was on my G8's before the Catch Can.
That does not mean that there is no buildup on the valves etc.... Also, now that I am spraying 50/50 W/M occasionally, would guess that it helps clean out any carbon. Rarely get any boost volume to facilitate spray in normal driving, however.

 

[yamahaSHO]

The unit above is used as a swirl post to separate the mixture. Within that gas IS oil, fuel, etc.

Currently, on the SHO, I vent to a catch and the milky brown puke collected in there would cause the build-up seen on the inside of an intake.

 

[Laminar]

Fuel injectors on non-DI motors won't wash the intake. They're only a few inches from the cylinder/chamber with where they would be installed on the head.

On the 2.5 Duratec, it is designed with secondary butterfly valves in the lower intake manifold that open at higher RPMS. The injectors are aimed to spray fuel into the primary passageway of the LIM. For some crazy reason, the secondaries are always super dirty while the primaries are squeaky clean.

 

[yamahaSHO]

Not sure what you're trying to say... Sounds normal and logical to me.

 

[apex]

I love the thoughts on lower octane fuel in the ecoboost causing problems. I've own quite a few late model literbikes from Yamaha and Honda, I've raced those bikes on hot humid days with the cheapest fuel I could put into them with zero problems.


Now those bikes had a couple mild mods to put out close to 200hp at the crank which would translate to a 700 hp 3.5 liter engine N/A. If a engine with 13:1 comp tuned to that degree can handle the worst fuel possible I certainly laugh at the thought of a ecoboost dying from using the same grade of fuel.

 

[yamahaSHO]

I would imagine that effective compression on the turbo SHO motor is a good deal higher than your bike. My SC SHO is around 20:1 effective, IIRC. That's not counting the higher intake temps, much, MUCH larger load on the engine, etc.

 

[zach44102]

I just put a vaccum cap on my PCV,deleted it. No sludge in the intake system and the heads and valves are Spotless. I have pics to proove it. Only ill effect I have seen is the oil gets a little dirty faster. But I like the spotless heads and intake too much to care